I'm not a CPA so I won't delve into any tax implications for your portfolio regarding seller financing.As far as what terms are typical for my area, I am in Ohio, where you can buy houses cheap.

Being able to make more money from the property and financial justification is typically not considered a hardship.Could you put the property under contract contingent on going to ZBA and getting the other units approved?

This is the only scenario that clearly benefits the original owner but the benefit is typically only some high rent amount.In summary, the downside for the current owner is so much greater (loosing out to huge appreciation) and more likely to happen (historically the appreciation has been outstanding) than the upside (that the tenant does not exercise the option and the owner has been able to collect higher rent than a traditional rental).I did know a couple of tenants in San Diego that had a lease options. 

The cost of ownership typically catches owners off guard.

I'm curious to know what the typical rate, term and amortization is on a LOC like this.I tried searching for the posts that discussed this LOC but I had no like finding them.If anyone has information or insight they can share it would be appreciated.

Another thing to in mind is wholesale deals are cash deals so you typically can't get bank financing to close them. 

@Matt Carey honestly man we have success just using our handyman to remove it they typically have trucks or a small trailer and won't charge that much.

These typically are higher rate and easier to get to fund.There are also amortized 15-30 year loans that are based on DSCR, LTV, and credit.

How typically have landlords done this.  

Apartments are identical other than upgraded appliances, re-grouted bathrooms, and kitchen backsplash (along with much nicer paint colors).